new file: linear/linkedList.go

linear/linkedList.go

@@ -0,0 +1,108 @@
+package linear
+
+import (
+	"fmt"
+)
+
+type Node[T any] struct {
+	data T
+	next *Node[T]
+	prev *Node[T]
+}
+
+type LinkedList[T any] struct {
+	head   *Node[T]
+	tail   *Node[T]
+	length uint8
+}
+
+// InsertAtHead() -> inserts data and sets it as head
+func (ll *LinkedList[T]) InsertAtHead(data T) {
+	newNode := &Node[T]{data: data}
+
+	if ll.head == nil {
+
+		ll.head = newNode
+		ll.tail = newNode
+	} else {
+		newNode.next = ll.head
+		ll.head.prev = newNode
+		ll.head = newNode
+	}
+
+	ll.length += 1
+}
+
+// InsertAtTail() -> inserts node at tail
+func (ll *LinkedList[T]) InsertAtTail(data T) {
+	newNode := &Node[T]{data: data}
+
+	if ll.tail == nil {
+
+		ll.head = newNode
+		ll.tail = newNode
+	} else {
+		newNode.prev = ll.tail
+		ll.tail.next = newNode
+		ll.tail = newNode
+	}
+
+	ll.length += 1
+}
+
+// PrintList() -> prints linked list head to tail
+func (ll *LinkedList[T]) PrintList() {
+	current := ll.head
+
+	for current != nil {
+
+		if current.prev != nil {
+			fmt.Print(" <--> ")
+		}
+
+		fmt.Print(current.data)
+		current = current.next
+	}
+	fmt.Println()
+}
+
+// Data() -> returns a pointer to head.data
+func (ll LinkedList[T]) Data() *T {
+	if ll.head == nil {
+		return nil
+	}
+
+	return &ll.head.data
+}
+
+// DeleteHead() -> deletes front node if there is a node to delete
+func (ll *LinkedList[T]) DeleteHead() {
+	if ll.head != nil {
+		if ll.head == ll.tail {
+			ll.head = nil
+			ll.tail = nil
+		} else {
+			ll.head = ll.head.next
+			ll.head.prev = nil
+
+		}
+
+		ll.length -= 1
+	}
+}
+
+// DeleteTail() -> removes end node
+func (ll *LinkedList[T]) DeleteTail() {
+	if ll.tail != nil {
+		if ll.head == ll.tail {
+			ll.head = nil
+			ll.tail = nil
+		} else {
+			ll.tail = ll.tail.prev
+			ll.tail.next = nil
+
+		}
+
+		ll.length -= 1
+	}
+}